Telephone exchange system



May 12, 1931'. c. B. FOWLER 1,804,409

TELEPHONE sxcnmes SYSTEM Filed'Feb. 12,1950

/Nl/EN7O/? C. B. FOWLER A TTOPNE) Patented May 12, 1931 UNITED] stares PATENT OFFICE crnnnnonln; rowrnn, or QUEENS VILLAGE, NEW Y RK, ASSIGNOR T BELL 'rnLn.

PHONE raro m'ronrns, mconronazrnn, or vnw YORK, n. Y., A CORPORATION or NEW, YORK crnnternonn ma iacs sizs'riim 1 Application filed February 12, 1930. Serial No. 427,677.

This invention relates to telephone e2;- change systems and particularly to systems in whichthe service charge is based on the duration of conversation. V The objects 'areto eiiect economy in the use of equipment and to secure greater reliability in the operationof the centralofiice controlling circuits. r

It has been proposed in the past to charge a .calling subscriber'for the service rendered by means ofa meter, located at his substation, which" operates in response to reversals of 1 currentinthe calling line at'successive intervals during the eriod the conversational connection is established between his line and the called line. To this end acurrent' reversing'device is provided at the central office and isrendered effective either when connection is completed to the calling line, as by the insertion of the answering plug ofa cord circuit, or when thecall'ed' party answers. In systems involving operators cord circuits, the process of reversing current may result in the repeated; release and operation of the answering supervisory relay, "causing the According to the present invention, animprovement is secured-over prior systems by the provision-0f an equipment common to a number ofcord circuits so arranged that the contacts of the supervisory relays of all related cords are shunted by short-circuits applied during the period thesource of current is in a reversed condition. This permits the i 5 supervisory relays to releasewithout causing 7 the lamps to flicker.

This invention has been shownin the ac-' companying drawing inwhich'it has been in "corporated in acord circuit well known in the '40 art, A calling subscribers line and'a called "subscribers linehave' also been shown I called subscriber wi'll'now be made. "When the operator inserts plug 2'ofcord circuit A into jackBojf a calling'subscribersline 1, the

supervisory relay-'5 is operated, over an obvious circuit through the subscribers loop and the supervisory 1amp'7 which wouldordinarily be lighted in the usual manner through the sleeve circuit will therefore not be lighted in this case due to the short circuit established therefore by the operation of relay 5.

Relay 5 in operating causes relay 8 to operatein a circuit from battery, winding of relay 8, armature and'front contact of relay 5, to

ground through the sleeve circuit. Relay 8 is 7 common to a plurality of cord circuits such as A andwill presently cause the operation of" another relay 10 which is also cornmonto the same plurality of cord circuits as will hereinafter be described. I

The operator now actuates a talking key 11 to connecther telephone set across the tip' scribers line 12 by inserting'plug 13 into jack 14. The supervisory lamp 15 is thereby lighted through the sleeve circuit. The subscriber may now be rung in the usual manner through the operation of a ringing key (not shown) and when the subscriber answers the call the supervis'oryrelay 16 operates through the subscribers loop in the usual manner. Relay 16in operating establishes a circuit for the operation of relay 17 from battery, windingof this relay, armature and front contact of relay 16, to ground through the sleeve circuit'at-plug 13 and jack 15. The operation of relay 17 disconnects the normal talking battery supply from the tipfand ring conductors ofthe cord and connects these conductors to themeteroperating'battery which also serves as the talking battery for the calling subscribers line while the called subscribers line is connected thereto. The polarity of this batcontrol of interrupter 18 and relay 19, as is well known in the art, and cause the periodic operation of the meter 20 in the calling sub scribers line to register a call. 1 I Referring new again to the effect produced by the-operation of relay 8;; The interrupter 21 and relay 22 are common to a large number of cord circuitssuch as A and preferably common to all COI'd'ClIClllllS m an exchange,

whereas relays such as 10, 23 and 2 1 are indicircuit 'par'tially' closed by the operation of relay 8, will be completed to ground to cause the operation of relay 10. Relays 23' and'24s will also be operated during this period pro vided the relays corresponding to relay 8 for other groups are operated. hen relay-1O operates a short-'circuit'is closed around the armature-and front contact of the supervisory relay 5 so as to prevent the circuit for lamp 7 to be completed durlng thereversal of the battery, wh ch might occur 1f relay 5 is released while this reversal 1s taking place. That is the interrupter 21 is so arranged in relation to interrupter 18 that relays 22 and 10 will only be operated while the battery is reversed. Consequently lamp 7 will not givefalseindications during the period a connection is established. 7

Vixen the called subscriber disconnects, the supervisory relay 16 is released which causes the release of relay 1'? to disconnect the meter operating and talking battery and cause the normal talking battery for the calling subscribers line to be replaced when the calling subscriber hangs'up his receiver on the hook, relay 5 will release and lamp 7 light to indicate this condition. The operator may then remove the plug 2 from ask 3, and plug 13 from jack 14 in the usual manner.

It should be understdod that while the invention has only been illustrated in connection with one cord circuit, it may readily be applied to other circuits without departing from the spirit thereof.

' erate the registers thereof, supervisory relays,

lVhat is claimed is: 7 I 1. In a telephone system, calling lines, called lines, connecting circuits for 1n'tercon 'nectingthe calling lines with said called lines, registers for the callmg lines, a source of current for supplying the calling lines, means for periodically changing the condition'of the flow of current m'the calling lines to opone for each connecting circuitand} arranged to be included in the calling line circuit during conversation, signals, each controlledby a respective one of said relays, and means a common to a number of said c'onnec'ting circuits for removing said signals from the control of the corresponding relays during the period the current in the calling lines is in a changed condition.

2. In a telephone system, calling lines, called lines, meters for said lines, connecting circuits for connecting acalling line with a mon to a number of said connecting circuits for maintaining the signal in non-operated condition when the. battery reversal takes place.

3. In a telephone system, calling lines, called lines, meters for said lines, connecting circuits for connecting a calling line with a called line including [a supervisory relay and a signal, meter operating means including a battery reversing device and arranged to operate the meter of the calling subscrib-- ers line when aconnection is established and the battery is reversed, means for maintainingthe supervisory relay operated while a connection is established and no battery reversal takes place, means for maintaining the signal in a non-operated condition-in response to the operation of the supervisory relay, and means common to a. plurality of connecting circuits for maintaining the sig-. nal-in a non-operated condition if said relay is released duringrev'ersal of current.

4. In a telephonefsystem, calling 3 lines, called lines, meters for said lines, connecting circuits for connecting'calling lines with called lines, a supervisory relay and a signal for each connecting circuit, a meter operating device including an interrupter, a battery supply and means controlled by said interrupter for alternately reversing connections from said battery supply tosaidcalling line to operate the meter thereat, means for maintaining said-signal in a non-operated condition in response to, the'operation of the supervisory relay, means for main taining said supervisory relay operated-in H response to the connection from said battery when applied to the calling line in one direction or the other, an interrupter commonto a plurality of connecting circuits, said second interrupter being synchronized with said first interrupter to maintain said signal? in non-operated condition when current from said battery is reversed-from one direction to the other.

5'. In a telephone system, calling lines, called lines, meters for said lines, connecting circuits for connecting a calling line with a called line including asupervisory rela and a signal, meter operating means includ ing-a battery reversing. device, means for maintaining "the supervisory relay" operated while a connection is established'when no battery reversal takes place,means for maintaming the signal in a. non-operatedcondibattery supply, means controlled by said interrupter for alternately reversing connections from said battery supply to said calling line to operate the meter thereof, means for maintaining said supervisory relay operated in response to the connection from said battery supply when applied to the calling line 1n one direction or the other, means for maintaining said signal in a non-operated condition in response to the operation of the supervisory relay, another interrupter common to a plurality of connecting circuits for maintaining'said signal in non-operated condition, and means for synchronizing said interrupters so that the period of maintaining said signal in non-operated condition by said second interrupter overlaps the period of reversal'of current from said battery to the line.

7. In a telephone system, calling lines, called lines, meters of said lines, connecting circuits for connecting a calling line with a called line including a supervisory relay and a signal, meter operating means including a battery reversing device'and an interrupter, means for maintalning the supervisory relay operated while a connection is established and no battery reversal takes place, means for maintaining the signal in a non-operated condition in response to the operation ofthe supervisory relay, and means common toa plurality of connecting circuits including another interrupter for controlling the maintenance of the signal in a non-operated condition for the; period during which the re versal of current from said battery to the line takes place. 7

In witness whereof, I hereunto subscribe my name this 10th day of February, 1930.

' CLARENCE B. FOWLER. 

